The objectives of the proposed studies, as in previous years, can be summarized as follows: (A) To continue to define subcategories of immunologic deficiency syndromes, based on inheritance patterns and on immunogenetic and biochemical methods which are standard genetic tools (the current WHO Expert Committee on Immunodeficiency states that the current classification of immunodeficiency disorders is admittedly incomplete, and indeed several disease entities listed as such have since been shown to be heterogeneous syndromes). (B) To see whether the separate diseases within a given "syndrome" are different in clinical and laboratory features. (C) To search for close associations and possible linkage between one or another subcategory of immunodeficiency syndrome and immunogenetic genotypes. (D) To continue to develop new test methods to further assess deficiencies in those cells associated with immunodeficiency (e.g., T and B cell populations, monocytes, granulocytes).